Lecture 20 Flashcards
Characteristics of Mollusca
-they have Calcareous Shell enclosing soft body
-moll=soft
-open circulatory system
-foot used for movement
-visceral mass above foot
-mouth called a radula
-not segmented
What are gills used for in Mollusca
Gas exchange and feeding
What are Gastropoda
-snails & relatives
-single, coiled, tubular shell
-torsion during development
What are Nudibranchs
Sea slugs (no shell)
What are Class Bivalvia
Clams, oysters, mussels, scallops
-two hinged shells
Characteristics of Bivalves
-feed by filtering water through gills
-No radula (no head)
-some are sessile
-mostly sedentary
What are Class Cephalopoda
Squids, cuttlefish, octopuses
-no external shell
-long tentacles around mouth
Why do Nautilus differ from other Cephalopoda
They have a shell
Characteristics of Cephalopods
-all predatory: radula modified as a beak
-the only molluscs with a closed circulatory system
-have a siphon
-excellent maternal care
-excellent vision
-complex behaviour
What is a siphon
a fused tube of mantle used for jet propulsion
What are Chromatophores
pigments in some cephalopods (octopus/squid) that can change colour, pattern, and texture of their skin.
